Where Do Hawaii's Great White Sharks Come From?

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Although it's a relatively rare occurrence, great white sharks
have occasionally been sighted near the Hawaiian Islands
throughout history (and even prehistory — teeth from white sharks
have been found in artifacts from ancient islanders).

The small number of sightings and lack of young sharks seen,
however, suggests that there isn't one group of sharks that lives
in the region, and that the animals that have been spotted are
drifters who have wandered far from their native waters. But
whence do they come?

A recent study compiled all records of great
white shark sightings around Hawaii in modern history — a
total of 13 — and all published reports of satellite-tracked
sharks that reached the region, a total of 22. By comparing the
records with data from tracking studies, it appears the sharks
most likely come from the population centered in the eastern
Pacific, along the west coast of Mexico and the United States.

Scientists came to that conclusion after noting that all of the
sharks seen in the fall around the Hawaiian Islands are female.
That matches the life history of the great
white sharks in the eastern Pacific. Female great white
sharks from this group complete a two-year migration from
Guadalupe Island, Mexico, where they mate, after which they roam
far and wide into the Pacific, before returning to Baja
California to give birth to pups (after which they go back to
Guadalupe Island). Males, on the other hand, complete a one-year
migration from the island, and thus wouldn't be around in the
fall.

Modern records of great white sharks "date back to May 1926, when
the remains of a man who apparently drowned in waters of Haleiwa,
Oahu, were recovered 16 days later in the stomach of a large
shark landed" nearby, the authors wrote in the study. The man, a
soldier, was identified primarily by his swim trunks, which were
issued by the U.S. Army.

"We learned that [great] white sharks occur in Hawaii across a
broader part of the annual cycle than previously thought — we
recorded observations from every month except November," said
study author Kevin Weng, a researcher at the University of Hawaii
– Manoa, in a statement from the school.